Electrical weighing systems with multiple incremental readouts

ABSTRACT

A weighing apparatus and method wherein an electrical analog signal, having a level representative of the weight of a load, is converted into a digital pulse train by an analog-to-digital converter. A counter for counting the converter-produced pulses is connected to one or more devices that provide a readout of the weight in visual and/or printed form. A program circuit is operatively connected to the converter and the counter, and selected circuit connections are made in the program for providing a selected one or more of the following conditions: (1) the division of the pulse train by a pre-selected divisor to count in only the quotient at the counter (2) the transfer of selected information from the counter to the readout devices to cause the weight to be read out by counting in any of a plurality of different increments such as ones, twos, or fives. Additional features pertain to tare circuits for taring the weightrepresenting signal.

United States Patent Godwin et al.

1541 ELECTRICAL WEIGHING SYSTEMS WITH MULTIPLE INCREMENTAL READOUTS 721lnventors: Gilbert Allan I Godwin, Oakland, N.J.;

Chapln A. Pratt, Rutl'and, Vt.

[731 Assignee: Howe Richardson Scale Company [22] Filed: July 27, 1970[21] Appl. No.: 58,259

[521 U.s.c ..177/1, 177 3, 177/210, l77/DlG. 3

511 Int.Cl. ..G01g3/14 5s FleldofSearch ..177/163',210,2ll,l,3,DlG.3

[56] I References Cited 1 UNITED STATES PATENTS 3,063,635 11/1962 Gordon..l77/2 0ux 3,192,535 6/1965 Watson ..l77/2l1x 3,324,962 6/1967'Morrisonm. ..l77/2l0 3,393,757 7/1968 Tonies 177/163 x 5/1969 Leonowicz......l77/2ll X 1 51 May 2, 1972 3,464,508 9/1969 Engleetal. ..l77/2llX3,525,991 8/1970 Kohler ..l77/2I I X Primary Examiner-Richard B.Wilkinson Assistant Examiner-George H. Miller, Jr. Attorney-Norris &Bateman 57 ABSTRACT A weighing apparatus and method wherein anelectrical analog signal, having a level representative of the weight ofa load, is converted into a digital pulse train by an analog-todigitalconverter. A counter for counting the converterproduced pulses isconnected to one or more devices that provide a readout of the weight invisual and/or printed form. A

program circuit is operatively connected to the converter and thecounter, and selected circuit connections are made in the program forproviding a selected one or more of the following conditions: (1) thedivision of the pulse train .by a pre-selected divisor to count in onlythe quotient at the counter (2) the transfer of selected informationfrom the counter to the readout devices to cause the weight to be readout by counting in any of a plurality of different increments such asones, twos, or fives. Additional features pertain to tare circuits fortaring the weight-representing signal.

26 Claims, 12 Drawing Figures VIIEIGHT CONTROL CIRCUIT WEIGHT SELECTIONPATENTEHMAY 2 m2 SHEET 2 0F 6 So am m m N INVENTORS GILBERT ALLAN eoowmCHAPIN A. PRATT ATTORNEYS mwzmo 555E hzoo 19:5

MTENTEUIW 21972 I r 3,659,665

- sum 30F e INVENTORS GILBERT ALLAN GODWIN CHAPIN A. PRATT ATTORNEYSPIKTEH'I'EU W 2 i973 3. 659 66 5 SHEET 0Fv 6 as I30 L AD 99 2 CELL 2FILTER GROSS-NET 42s 42s 394 i; 40 A, 39s

FIG. 8A

INVENTORS GILBERT ALLAN GODWIN CHAPIN A; PRATT ATTORNEY 5 PAWTFH 1.4M 21972 SHEET 5 0F 6 INVENTORS GILBERT ALLAN GODWIN CHAPIN A. PRATT zflwwIIIL 5 ATTORNEYS ELECTRICAL WEIGHING SYSTEMS WITH MULTIPLE INCREMENTALREADOUTS FIELD OF INVENTION This invention relates to weighing apparatusand methods. This invention is particularly concerned with the type ofelectrical weighing system wherein an electrical signal is developed asthe measure of a load applied to the weighing machine.

BACKGROUND Prior to this invention is has been the practice to utilizeforce-to-electrical signal transducers or load cells to measure theweight of a-load applied to the load-receivingmember of the weighingapparatus. Such transducers or load cells can produce an analog DC.signal voltage which is closely proportional to the weight of theapplied load.

More recently, a preference and need has developed for an electricallyproduced, digital readout in visual form, printed form, or both. As aresult, it became necessary to incorporate an electricalanalog-to-digital converter into the system to convert the analog,weight-representing signal into a digital representation. Some of theseconverters produce a train of pulses, the number of which isproportional to the magnitude of an applied analog voltage at a givenmoment.

Commercially available analog-to-digital converters vary in rating andcharacteristics which cause complications and difficulties when matchingthe converter to different load cell or scale capacities. In thisconnection it will be appreciated that an analog-to-digital converter ofa given rating or characteristic will only produce a predeterminedmaximum number of pulses in response to a predetermined analog voltagelevel. For example, the converter may produce 10,000 pulses in responseto a lO-volt signal. Each pulse, therefore, will represent an equal partof the input voltage.

In electrical weighing systems the analog signal voltage, such as the 10-pound volts mentioned above, is the result of the gain applied to aload cell potential by an amplifier To match the analog-to-digitalconverter the amplifier advantageously has a span of 10 volts. For a10,000-pound gross weight scale, the full span of 10 volts is readilyutilized since each pulse produced by the analog-to-digital converterwill represent and can be counted as 1 pound.

lf, however, the same 10,000-pulse converter is applied to a 5,000-poundscale, an upward gain adjustment to utilize the available span of 10volts would result in an erroneous readout of l0,000 pounds when a5,000-pound load is placed on the 7 scale. Prior to this invention, theforegoing complication was avoided by utilizing only a part of theavailable span. For a 5,000-pound scale, for example, only one-half ofthe available span is utilized. Thus, the application of a 5,000-poundload to the scale will produce a -volt signal, and the 10,000-pulseconverter will produce 5,000 pulses.

It will be appreciated that the foregoing technique will utilize only apart of the available gain, and for the example given above, the5,000-pound scale would be utilizing only one-half of the availablegain. In effect, therefore, this prior art technique constitutes adownward adjustment to a gain that is significantly less than the gainthat could be applied if it were not for the equipment utilizing thesignal. Such a downward adjustment from the available gain isundesirable and disadvantageous, for it significantly degrades theaccuracy and resolution of the system as compared with results thatcould be achieved by utilizing the full span of the amplifier.

SUMMARY AND OBJECTS OF INVENTION The circuit of this invention enablesanalog-to-digital converter and digital readout equipment of a givenrating to be applied to-a variety of different load cell or scalecapacities (i.e., gross weights), without a downward adjustment from theavailable load cell voltage gain and without the attendant disadvantagesassociated with such a downward adjustment from the available gain. Thisis one of the objects of this invention,

and it is essentially accomplished by maintaining a relatively high loadcell voltage gain and by dividing the pulse train produced by theanalog-to-digital converter by predetermined values.

Considering the foregoing example, the circuit of this invention enablesthe full span of 10 volts to be utilized for a 5,000- pound scale. Twiceas much gain is therefore provided as compared with the prior techniquementioned above. According to the present invention, a program circuitis connected between the analog-to-digital converter and a multi-decade8-4-21 BCD counter for counting the weight-representing pulses producedby the converter. When the 10,000-pulse converter is used in conjunctionwith a 10,000-pound scale, the full l0-volt span is utilized, and theprogram supplies all of the converter-produced counts to the counter.When the 10,000-pulse converter is applied to a 5,000-pound scale, thegain is adjusted to again utilize the full lO-volt span. Thus, theapplication of a 5,000-pound load to the 5,000-pound scale will producea l0-volt signal, and the 10,000-pulse converter will correspondinglyproduce 10,000 pulses. According to this invention, program circuitconnections will. now be made to connect a pre-stage divider between theconverter and the counter to divide the number of counter producedpulses by one-half. The counter will consequently only count one-halfthe number of converter produced pulses. Thus, a gross load of 5,000pounds produces a high gain analog signal voltage of 10 volts (i.e., thesame as that in the 10,000-pound capacity system). The converter willtherefore generate its maximum of 10,000 pulses, and this count will bedivided by two, leaving 5,000 pulses to be counted and displayed indecimal form.

According to a further aspect of this invention, at least the unitsdecade counter state in the multi-decade counter performs dividingfunctions, and in one embodiment is capable of dividing by twos andfives. By selectively arranging the electrical connections to thevarious terminals at the units decade counter stage, the readout orweight display device can be made to count in displayed increments ofones, twos, or fives. Moreover, selected circuit arrangements betweenthe prestage divider, the units decade counter and a latch formemorizing the BCD output of the counter provides a wide variety ofgross weight readouts and incremental counting conditions withoutchanging the analog-to-digital converted or the readout equipment. Forexample, either a gross weight of 10,000 pounds or 5,000 pounds may beread out by counting in displayed increments of ones, twos, or fives ina system having the previously mentioned 10,000-pulse converter. Usingthe same l0,000-pulse converter, a gross weight of 50,000 pounds may beread out, counting in displayed increments of fives.

The capability of causing a visual digital display to read out indisplayed increments that are greater than one is advantageous, forunder certain conditions, it tends to improve the stability of thedisplayed count. For example, the display may sometimes alternatebetween two successive numbers or counts in its lowest order decadeowing to such factors as noise pickup and other things. For anilluminated display, the readout will therefore flicker making theobservation of the number more difficult. By not displaying the totalnumber of converter pulses, the chances of observing the alternation arereduced. As a result, the readout will be more stable.

Furthermore, the capability of reading out the weight in displayedincrements greater than ones widens the versatility of the systemwithout requiring a change in the analog-to-digital converter or thereadout equipment. For example, a gross weight of 50,000 pounds, aspreviously mentioned, may be counted and displayed even though themaximum pulse outthe latch to a fixed logical state, thereby renderingthem inoperative. For each converted-produced counter pulse counted bythe units decade counter stage, the logical state at the weight-of-lposition of the counter output is changed, and this information istransferred to both the l and 4 weighted bit positions at the latchbetween the counter and the display. Since the I and 4 weight bitpositions in BCD add up to a 5, the display will respond to each countedpulse by successively displaying zeros and fives at its units decade.Thus, the display is operative to read out a gross weight of 50,000pounds in displayed increments of fives.

According to another feature of this invention, a latching circuit isconnected between the multi-decade BCD counter and the readout device tomemorize the BCD information at the output of the counter in response toa command signal, and a feedback circuit is provided between the outputof the latching circuit and a summing junction at the input to the loadcell conditioning'amplifier. The output of the load cell will also beconnected to this summing junction, and the feedback circuit contains adigital-to-analog converter which upon command will sample the BCD datainformation and memorize or hold the sampled information. Thedigital-toanalog converter converts the memorized information into anequivalent analog signal voltage which is fed back to the amplifierinput summing junction with a polarity that tares out the existing loadcell signal at the summing junction. By utilizing a bi-polaranalog-to-digital converter with this taring arrangement, the amount ofmaterial removed from a storage hopper or silo can be read out byweighing the material in the hopper before and after a portion of it isdispensed.

This invention also provides another form of tare circuit which may beutilized when the tare weight of the truck or container is known or canbe determined by weighing the vehicle or container. The tare signalprovided by this second form of tare circuit is selectively set bysuitable means (such as a potentiometer) and is applied to the readoutcircuit in such a manner that it is converted by the analog-to-digitalconverter and read out in the digital readout device. This form of tarecircuit is convenient to operate, inexpensive to manufacture, andutilizes the available high resolution of the electrical digitalconversion and readout equipment.

In addition to the foregoing objects, another object of this inventionis to provide a novel batch weighing system in which delivery of aplurality of materials for making up a batch formula is controlled byanalog signals and in which readout of the weight of delivered materialsis in digital form.

These and other objects will appear as the description proceeds inconnection with the appended claims and the below-described drawings.

DESCRIPTION OF DRAWINGS FIG. 1 is a partially functional, schematicdiagram of a batch weighing system according to one embodiment of thisinvention;

FIG. 2 is a partially functional, schematic diagram of the electricalweighing circuit shown in FIG. 1;

1 FIG. 3 is a BCD truth table showing the logic states for the countersillustrated in FIG. 2; I

FIG. 4 illustrates the counter program circuit connections for readingout a gross weight of 10,000 pounds by counting in displayed incrementsof ones;

FIG. 5 is a schematic of the counter program circuit connections forreading out a gross weight of 10,000 pounds by counting in displayedincrements of twos;

FIG. 6 is a schematic of the counter program circuit connections forreading out a gross weight of 10,000 pounds by counting in displayedincrements of fives;

FIG. 6A is a schematic of the counter program circuit connections forreading out a gross weight of 5,000 pounds by counting in displayedincrements of ones;

FIG. 7 is a schematic of the counter program circuit connections forreading out a gross weight of 50,000 pounds by counting in displayedincrements of fives;

FIG. 8 is a schematic showing the application of the weighing andreadout circuit of this invention to a vehicle plat form type scale andfurther showing a special tare circuit for taring out the load celloutput signal voltage;

FIG. 8A illustrates another form of tare circuit;

FIG. 9 is a schematic diagram of the analog cut-off and weight selectioncircuit in FIG. 8; and

FIG. 10 is a schematic diagram showinganother application of the tarecircuit illustrated in FIG. 8.

DETAILED DESCRIPTION The embodiment shown in FIG. I is a batch weighingsystem for weighing out pre-selected weights of one or more ingredientsin a batch formula. Preferably, the mechanical equipment for theembodiment shown in FIG. I is essentially the same as that described inGerald C. Mayers pending patent application Ser. No. 658,229 (now U.S.Pat. No. 3,528,518) filed on Aug. 3, 1967 for Automatic Batch Weigherand assigned to the assignee of this application. It will beappreciated, however, that any appropriate, suitable form of mechanicalscale equipment may be utilized in conjunction with this invention.

In general, the batch weighing apparatus shown in FIG. 1 comprises astorage hopper or bin 20 having an open bottom 22 for delivering a firstfluent or particulate material in a layer upon an endless belt of aconventional power-driven feeder 24. Feeder 24 has an upper belt flight26 which is horizontal and which moves from left to right in FIG. 1between pulleys 28 and 30. An electric motor 32 is connected to pulley30 by an endless chain 34 to advance the belt. A manually operateddischarge gate 36 may be provided to cut off the delivery of materialfrom bin 20 to feeder 24. The material passing through the open bottom22 of bin 20 is advanced in a layer on the upper belt flight 26 offeeder 24. This material falls off the end of the flight as it passesaround pulley 28 and descends in a freely falling, continuous columninto a weigh-hopper 38. In this embodiment, feeder 24 is employed todeliver material to hopper 38 at a full flow rate. Unshown feeding meansmay be employed if desired to deliver material at a dribble feed rate tothe weigh hopper.

To deliver a second material to weigh-hopper 38, an additional feeder 60is provided for and may be of the same construction as feeder 24, asshown in FIG. 1. Accordingly, the parts of feeder 60, which are the sameas the parts of feeder 24, have been designated by like referencecharacters suffixed with the letter a. Unshown dribble feed apparatusmay be provided for the second ingredient as mentioned in connectionwith feeder 24. In general, it will be appreciated that any suitablearrangement of feeding may be employed.

As shown in FIG. 1, weigh-hopper 38 is provided with a discharge gate 66for controlling the discharge of material through the open bottom of thehopper by gravity. Gate 66 is opened and closed by a suitable fluidmotor 68. A valve 70 actuated by a solenoid 72 controls the supply andexhaust of fluid for operating motor 68.

With continued reference to FIG. I, a pivotally mounted catch gate 73 isinterposed between feeder 24 and hopper 38. A suitable fluid motor 74swings gate 73 about its pivot axis between its full line and dottedline positions to respectively permit and interrupt delivery of materialfrom feeder 24. A valve 75 actuated by a solenoid 76 controls the supplyand exhaust of fluid for operating motor 74. By operating solenoid 76,motor 74 is actuated to cause gate 73 to open, permitting feeder 24 todeliver material to hopper 38.

Feeder 60', as shown in FIG. 1, is also provided with a catch gate andfluid motor operator of the same construction as that just described forfeeder 24. Accordingly, the catch gate and catch gate operator structurefor feeder 60 has been identified with like reference numerals sufiixedby the letter a, as shown.

A suitable lever system may be provided for supporting hopper 38 and isschematically shown in FIG. I to comprise a fulcrumed lever 80 which ispivotable about an axis provided by a knife edge and a fulcrum assembly82. Hopper 38 is pivotally suspended from lever 80 by a suitable knifeedge assembly indicated at 84. On the side of the knife edge assembly 82opposite from hopper 38, lever 80 is operatively connected to the inputside of a suitable force transducer which may be a load cell indicatedat 86. Load cell 86 may be of the conventional silicon or resistancestrain gauge type and is excited by a suitable D.C. power supply sourceindicated at 88 in FIG. 2. Load cell 86, of course, may be connected -toany suitable operative scale or lever part, which moves in proportion tothe weight of delivered material. Alternatively, it will be appreciatedthat in place of the lever and load cell arrangement shown in FIG. 1,hopper 38 may be supported directly on a plurality of load cells whichare type.

As shown in FlG..1, the weight-representing, analog output signalvoltage of load cell 86 is supplied to a signal conditioning,processing, and readout circuit generally indicated at 89. As will bedescribed in greater detail later on, circuit 89 provides a digitalreadout in visual form, printed form, or both. Circuit 89 also suppliesan analog signal voltage, which is proportional to the weight ofmaterial delivered to hopper 38, to an analog weight control circuitgenerally indicated at 90.

The analog weight control circuit 90 is preferably the same as thatdescribed in the above-mentioned U.S. patent application Ser. No.658,229 (now U.S. Pat. No. 3,528,518). In brief, it has acomparatornetwork or module 93 that compares the scale output signal-which isdeveloped by load cell 86 and which represents the weight of materialdelivered to scale hopper 38-with a pre-set weight selection signalvoltage. The weight selection signal voltage is developed by a weightselection device or circuit 94 and represents the desired or preselectedamount of material to be delivered to hopper 38. In response to thissignal comparison, comparator network 93 produces an error signal whichis operative upon reaching a predetermined value to perform the desiredfunctions in a batching operation. More specifically, circuit 90, inresponse preferably of the strain gauge .to the above-mentioned errorsignal, will control the operation of motor 32 and 32a and solenoids 76,the following sequence of operation:

Motor 32 is first energized to start operation of feeder 24 and thecatch gate 73 is opened, thus allowing material from feeder 24 to bedelivered to hopper 38. The load cell developed, weight-representingsignal voltage is compared with the pre-set signal voltage from circuit94. When the desired amount of the first material is delivered to hopper38, circuit 90 responds to the comparison-produced error signal tode-energize motor 32 and to close catch gate 73, thus interruptingdelivery of the first material to hopper 38. Motor 32a is then energizedto start operation of feeder 60, and catch gate 73a is opened, thuspermitting material from feeder 60 to be delivered to hopper 38. At thesame time, the weight selection circuit 94 supplies to circuit 90 asecond pre-set signal voltage which is proportional to the desiredamount of the second material to be delivered to hopper 38. This secondpreset signal voltage is compared with the load cell-developed,weight-representing signal to produce the above-mentioned error signal,and when the error signal again reaches a predetermined magnitude,circuit 90 de-energizes motor 32a and closes catch gate 73a, thusstopping operation of feeder 76a, and 72 to provide 60 and interruptingthe flow of material from feeder 60 to hopper 38. As fully described inco-pending application Ser. No. 658,229 (now U.S. Pat. No. 3,528,518),circuit 90 is programmed to operate solenoid 72 for opening dischargegate 66 and thus discharging the load accumulated in hopper 38.

Weight selection circuit 94 may be of the same construction as thatdescribed in the above-identified U.S. patent application Ser. No.658,229 (now U.S. Pat. No. 3,528,518).

Referring to FIG. 2, load cell 86 conventionally comprises a bridge 98having its output connected through a summing resistor 99 to a summingjunction 100 for a signal conditioning, operational amplifier 102. Thepower supply source 88 is connected across theinput terminals of theload cell bridge 98 as shown. A variable feedback resistor 104 couplesthe output signal voltage of amplifier 102 back to junction to provide aspan adjustment for the voltage range impressed upon the circuit.Operating power for amplifier 102 may be derived from any suitablesource.

A dead weight tare adjustment is provided by a potentiometer 116 havinga movable wiper or am 118 which is adjustable along a resistor 120. Thevoltage impressed on wiper 188 is supplied through a summing resistor121 to junction 100. The load cell output signal voltage and the deadweight potentiometer signal voltage will be opposite in sign. Wiper 118is adjusted to offset or tare out the weight of scale .parts acting onload cell 86 to thereby provide a zero amplifier input voltage signalcondition at junction 100 when hopper 38 is empty. Thus, the algebraicsummation of signals at junction 100 will be closely proportional to theamount of material delivered to hopper 38. Amplifier 102 together withits summing junction and resistor summing network form a part of circuit89. Amplifier 102, resistor 121 with its summing junctionand resistorsumming network, may be in the form of a printed circuit on a printedcircuit card. The remaining components and circuits or networks incircuit 89 may also be modularized and formed on printed circuit cards.

As shown in FIG. 2, the additional modules making up circuit 90 includea filter 130, an analog-to-digital converter 132,

and components of a counting and memorizing circuit which will bedescribed in detail later on.

With continued reference to FIG. 2, the amplified output signal voltageof amplifier 102 is supplied to filter which filters out any A.C.component that may be superimposed on the D.C. signal. Desirably, filter130 is of the low pass type having good frequency and time responsecharacteristics to develop a filter output signal which is substantiallyfree of A.C. components that might interfere with the trouble freeoperation of circuit 89. Preferably, filter 130 is a four-pole low passfilter that is made up by connecting two two-pole low pass filters inseries. Each of the two-pole filters preferably is of the form describedin pending application Ser. No. 854,994 filed on Sept. 3, 1969 forElectrical Filters for Weighing System Circuits and assigned to theassignee of this application.

The amplified and conditioned, load cell-developed signal voltage at theoutput of filter 130 is applied to the input of the analog-to-digitalconverter 132. Converter 132 is of any suitable,,appropriate fonn forvproducing a digital representation that is related to the level of theweight-representing analog signal voltage applied to the input of theconvertenln this embodiment, the digital representation is in the formof a recurrent,'fixed frequency (i.e., equal time separation betweenpulses) pulse stream or train in which the number of pulses in thestream is proportional to the level of the weight-representing analogsignal voltage at the time when the analog signal is sampled.

A sample rate trigger circuit produces a recurrent trigger signal whichis applied to converter 132. In response to each trigger to a converter132 samples the weight-representing analog signal which is supplied toit by filter 130. Converter 132 translates each sampled analog signalinto a series of pulses of equal time separation, and, as mentionedabove, the number of pulses in each series will be proportional to thevoltage level of the weight-representing analog signal. The pulses ineach series are serially routed through from the output of converter 132to a multi-decade BCD (Binary Coded Decimal) counter circuit generallyindicated at 142 in F IG. 2. In this embodiment, the range of converter132 is, by way of example, 0 to 10,000 pulses.

At the end of each recurrent, weight-representing pulse train converter132 is conventionally equipped to supply a latching signalanalog-to-digital line 152 to a latching network 154. latching network154, as will be described in greater detail later on, is connected tothe output of counter circuit 142, and when the latching signal isreceived from converter 132 it latches in and thereby memorizes the BCDoutput of counter circuit 142. It will be appreciated that the number ofconverter pulses loaded into counter circuit 142 at this time will besubstantially proportional to the level of the analog signal supplied byfilter 130 at the time when it was sampled. The sample rate triggercircuit 140 may also be connected by I a line 266 to counter circuit 142to supply a reset signal that resets the counter circuit to zero at thebeginning of each sampling or conversion period.

Trigger circuit 140 may be of any suitable appropriate form and it maybe incorporated as part of converter 132. One form of trigger circuitprovides a saw-tooth like signal voltage by cyclically charging anddischarging a capacitor. The repetition rate of the saw-tooth signalvoltage will determine the rate at which the weight-representing analogsignal voltage is sampled.

Counter circuit 142 comprises a series of conventional BCD electronicdecade counters 160, 161, 162, 163, and 164 each having a four-bit8-4-2-1 BCD output and respectively representing the units, tens,hundreds, thousands and tens of thousands digits in a weight-indicating,multi-digit decimal number to be displayed by a visual, digitaltranslator and display device 170. Counter 160 performs dividingfunctions and is advantageously a monolithic type SN 7490 having adivideby-two stage and a divide-by-five stage. The BCD output pins ofcounter 160, as well as the BCD output pins of counters 161-164, arerespectively designated by the reference characters A, B, C, and D. Thebinary weights assigned to pins A, B, C, and D for each counterrespectively are 1, 2, 4, and 8 as shown. To cause this type of counterto operate as a BCD counter, the A-output pin (weight of 1), which isthe output of the divide-by-two stage, is connected by a jumper to theinput pin of the divide-by-five stage to transfer the output of thedivide-by-two stage into the divide-by-five stage.

The truth table or BCD count sequence for each of the counters 160-164is shown in FIG. 3. From this table it is clear that for each pulsesupplied to the divide-by-two stage of counter 160, the signal state atpin A will change. The counter will automatically reset at the 10thpulse.

Counters 161-164 advantageously are the same as counter 160 and areconnected as shown so that each performs a divide-by-IO function. Forthe type SN 7490 counter this is accomplished by connecting the D-outputpin of counter 161 to the divide-by-two stage input of counter 162, byconnecting the D-output pin of counter 162 to the divide-by-two stageinput of counter 163, and by connecting the D-output pin of counter 163to the divide-by-two stage input of counter 164.

With these connections, each of the counters 161-163 will supply thecount of l to the next succeeding counter for every 10 counts cominginto the counter.

It will be appreciated that the number of counters employed in circuit142 will depend upon the number of decades that are desired in thenumber to be displayed. The input and the output connections for counter160 and input connection for counter 161 will be described shortly.

Still referring to FIG. 2, latch network 154 comprises a series of BCDdata word storage or memory latches, 172, 173, 174, 175, and 176, onefor each of the counters 160-164. Latches 172-176 advantageously are ofthe four-bit quad type SN 7475, each having four storage devices forstoring a fourbit data word and the complement thereof. For this purposeeach of the four storage devices in each latch has a Q to 6 output asindicated. Each storage device also has a data bit input pin and amemory or latch pin. The data words to be stored in latches 172-176 aresupplied by counters 160-164 respectively. The weights of the binary bitpositions at the output of the latches are as shown. The logical statescorrespond to the truth table shown in FIG. 3.

For the foregoing type of latch, the latching signal line 152 isconnected to the latch pins of each storage device in latches 172-176.When converter 132 supplies the proper logical state on line 152,whatever binary states that are present on the data input pins oflatches 172-176 will be transferred to and stored on the Q-output pinsof the latches, and the complements will be stored on the Q-output pins.

As shown, the A, B, C, and D output pins of counter 161 are connected inparallel to the four data input pins of latch 173. Similarly, the A, B,C, and D output pins of counter 162 are connected in parallel to thedata input pins of latch 174, the output pins A, B, C, and D of counter163 are connected in parallel to the data input pins of latch 175, andthe four output pins A, B, C, and D of counter 164 are connected inparallel to the four data input pins of latch 176. The connectionsbetween counter and latch 172 will be described shortly.

The information in counters 161-164 is transferred in parallel tolatches 173-176 respectively. Selected information from the output ofcounter 160 will also be supplied in parallel to latch 172 in a mannerto be explained in detail later on. Latches 172-176 memorizethisinformation when the proper latching logical state is supplied byconverter 132 as previously described.

The output pins of each of the latches 172-176 are connected in parallelto one module in device 170. In this embodiment device will have fivemodules, one for each of the latches 172-176. Device 170 may be of anysuitable, conventional form for accepting a BCD input at a relativelylow voltage level and for generating at each module the correspondingdecimal output 0 through 9. The modules are grouped to provide themulti-digit display as illustrated in FIG. 2. One type of device 170 isSigma 7 Model 32, manufactured by Sigma Instruments, Inc. of Boston,Massachusetts. In converting back to decimal form, the truth table inFIG. 3 may beutilized to determine the number that device 170 willdisplay in response to the data information latched on the Q-output pinsof latches 172-176. Considering the units module of device 170 and itsassociated latch 172, for example, the numeral l will be displayed whenthe memorized data word is 0001. If the memorizeddata word is 0010, thenumeral 2" will be displayed in the units module of device 170. If thememorized date word at the output of latch 172 is 0 I01, the numeral .5"will be displayed by the units module of device 170, and so on. A numberof fixed zero display modulesmay be added to device 170 to displaylarger digit numbers.

Counters 160-164 may be provided on one or more printed circuit cards.Likewise, latches 172-176 may be provided on one or more printed circuitcards.

Advantageously, the O-output pins of each of the latches 172-176 areconnected to a printer solenoid and solenoid driver circuit 181 ofsuitable form. Circuit 181 contains the solenoids for operating type ina printer 182. The data words memorized by latches 172-176 are operativeto select those solenoids that will, upon energization, actuate printer182 to print out the weight in decimal form. Power. for the printersolenoids is supplied from, a'suitable source 183 through a switch 184.Switch 184 may be actuated by a selectively applied switch controlsignal to electrically connect source 183 to circuit 181. The powersupplied from source 183 will energize those printer solenoids that wereselected for energization by the BCD data from latches 172-176.

As will be described in detail shortly, a program circuit (FIG. 2)provides the circuit connections for counters 160 and 161, latch 172 anda pre-stage divider 194 to selectively enable the device 170 to displaythe counts in increments of ones, twos; or fives. Operation of thecircuit thus far described will now be reviewed.

After the desired weights of the materials to be delivered to hopper 38are selectively pre-set in the weight selection circuit 94, controlcircuit 90 is activated to start feeder 24 first, and gate 73 will beopened to beging the delivery of the first material to hopper 38. Asmaterial is delivered to hopper 38, the output signal of load cell 86increases. The load cell signal voltage is conditioned by amplifier 102and filtered by filter 130, and from filter 130 it is applied to circuit90 where it is continuously compared with the pre-set signal voltage(representing the desired weight) supplied by the weight selectioncircuit 94. At the same time, the conditioned and filtered load cellsignal voltage is applied to the input of converter 132 where it iscontinually sampled at a pre-selected 9' repetition rate in the mannerpreviously described. The frequency at which the samples of the analogsignal voltage are taken will be determined by the frequency of thetriggering signal supplied by circuit 140.

Each time circuit 140 applies a triggering signal to converter 132,converter 132 responds by sampling the weightrepresenting analog signalvoltage. Thus for each sample converter 132 will produce a series ofpulses in which the number of pulses is proportional to the voltagelevel of the analog signal supplied by filter 130. Theconverter-produced pulses are routed by line 150 to counter circuit 142and will be loaded into the decade counters, starting with counter 160and then progressing to each successive decade counter as transferoperations are preformed. At the completion of each weight-representingpulse train, converter 132 supplies a latching signal over line 152tocause latches 172-176 to memorize whatever data information that wasloaded into counters 160-164 by the weight-representing train of pulsesfrom converter 132. The latch signal thus marks the end of theanalog-to-digital conversion, and the BCD- data information equivalentto the sampled analog filteroutput voltage will be stored on the outputpins of latches 172-176 as previously described. The BCD datainformation latched in on the output pins" of latches 172-176 will besupplied to display device 170 to cause device 170 to display the weightof the material delivered to hopper 38 asa multi-digit decimal number.

At the termination of the triggering signal, counters 160-164 areresponsive to the trailing edge of the triggering signal to reset tozero. Latches 172-176 are self-clearingin that previously memorizedinformation will be erasedv or removed by the transfer and memorizationof new information. In this manner, the weight-representing analogvoltage from the output of filter 130 is periodically sampled at apreset rate and read out in a visual display by operation of displaydevice 170.

When the desired amount of the first material is delivered to hopper 38by feeder 24 as determinedby the electrical comparison of the pre-setsignal voltage from circuit 94 with the analog signal voltage from theoutput of filter 130, circuit 90 automatically stops feeder 24 andcloses gate 73. Having thusly stopped the delivery of the first materialto hopper 38, circuit 90 then automatically starts feeder60 and opensgate 73a. As a result, delivery of the second material is initiated.

Circuit 90, as described in the previously identified application Ser.No. 658,229 (now US. Pat. No. 3,528,518) has an auto tare network ormodule 198 which automatically memorizes the weight of each materialdelivered to hopper 38 in a given batch formula. At theend of thedelivery of the first material the memorized signal voltage will beequal in magnitude to the weight-representing signal at the output offilter 130.

At the end of the delivery of the first material the memorized, autotare signal voltage, which is supplied by network 198, is applied tocomparator network 93 along with the output signal voltage from filter130 and the next pre-set signal voltage developed by circuit 94 andrepresenting the desired weight of the second material to be deliveredto hopper 38. The polarities of these three signals are such that inalgebraically summing the three signals at comparator network 93, theauto tare signal effectively cancels the signal voltage from filter 130.Thus, an unbalanced voltage condition represented by the second pre-setsignal voltage from circuit 94 will be impressed on comparator network93 in preparation for the delivery of the second material.

When feeder 60 is actuated and gate 73a is opened, the second materialis delivered to hopper 38, thus increasing the 7 output signal voltageof load cell 86 by a corresponding magnitude. Since this load cellsignal represents the total weight of materials delivered to hopper 38,device 170 will display the totalweight. Instead of applying theabove-mentioned auto tare signal voltage to comparator network 93, atthe end of the delivery of each material, the auto taresignal voltagemay alternately be applied to summing junction 100 as indicated at 143in FIG. 2 at the input of amplifier 102. The polarity of the auto taresignal voltage will be opposite to that of the load cell signal voltage.Thus, by algebraically summing the auto tare signal voltage along withthe load cell signal voltage and the other signal voltages at junction100, the output of amplifier 102 will reduce to zero when the auto taresignal voltage is applied to junction at the end of the delivery of eachmaterialto hopper 38. It is clear that the auto tare signal voltage willbe applied to the junction 100 only after the material is delivered tohopper 38. Thus, upon delivery of the above mentioned first material tohopper 38, the auto tare signal voltage, having a value equal andopposite in size to the load cell signal voltage, will be applied tojunction 100. As a result, the output of filter reduces to zero, and theanalog signal voltage that is applied to converter 132 as'the nextmaterial is delivered to hopper 38, will be proportional to the weightof the next material and not the total weight of materials in hopper 38.In this manner device and printer 182 will non-accumulatively read outthe weight of each material delivered to the hopper, rather than thetotal weight of the delivered materials. i

Referring back to the batching operation of the system shown in FIG. 1,it is clear that when the desired weight of the second material isdelivered to hopper 38, the comparison of signals at comparator network93 causes feeder 60 to stop and gate 73a to close, thereby terminatingthe delivery of the second material to the hopper. Discharge gate 66 maynot be opened to discharge the contents in hopper 38. v v In the systemthus far described it is apparent that circuit 89 is readily adaptableto provide a digital readout for a scale having a l0,000-pound'capacitybecause the capacity of converter 132 is 10,000 pulses. Thus, eachweight-representing pulse in the pulse stream produced by converter 132will be equivalent to 1 pound of material in hopper 38. Each of theconverter pulses loaded into counter circuit 142 and memorized by latchnetwork 154 is capable of causing the digital display in each decade ofdevice 170 to count in increments of one. Therefore, device 170 maydisplay a count up to 10,000 in increments of one.

Application of an analog-to-digital readout circuit to load cell scalesof different capacities, however, presents various complications owingto limitations imposed by the analog-todigital converter and thenecessary correlations between the analog-to-digital converter and thereadout device (visual, printed, or other form). Each converter willonly produce a maximum number of pulses and each pulse will beproportional to one part of a predetermined voltage range. In theexample given, converter 132 produces a maximum count of 10,000 pulsesin response to an analog voltage level input of 10 volts. It thereforeis necessary for a gross load of 10,000 pounds in hopper 38 to produce asignal voltage of 10 volts at the input of converter 132. This voltagelevel is achieved by the span adjustment at the variable resistor 104.

If the same amplifier span and the same digital readout circuit with thesame equipment is applied to a 5,000-pound scale, a gross load of 5,000input of converter 132, and converter 132 would consequently produce apulse count of 10,000 pulses to cause a readout of 10,000 pounds insteadof the desired 5,000 pounds.

In the past, the foregoing problem was avoided wherever possible byutilizing only a part of the available span at amplifier 102.

For example, the span for a 5 ,000-pound scale would be adjusteddownward to 5 volts to provide 5 volts at the input of converter 132,for a gross load of 5,000 pounds. This solution also has its drawbacksas compared with a system that is capable of utilizing the full span ormaximum gain available.

First, the signal-to-noise ratio will decrease because the gain atamplifier 102 is reduced to a value less than that which is available.In the example given, the gain is one-half of that which is available.The signal-to-noise ratio will consequently decrease since the line andcircuit noise error is not linear with respect to the gain.

pounds would apply 10 volts to the Second, 5 volts will now be resolvedinto 5,000 parts or pulses. Consequently, the full capacity of the10,000-pulse analog-to-digital converter will not be utilized. Theaccuracy and resolution of the system will be degraded. These are someof the disadvantages, and in addition to them, digital readout typeweighing systems proposed prior to this invention have a number of othershortcomings.

For example, prior systems do not provide the capability of optionallycounting in different displayed increments such as ones, twos, or fives.As previously mentioned it is sometimes desirable not to display thetotal number of converter pulses.

For example, displaying the weight-representing, converterproducedpulses in increments of twos or fives instead of ones, tends to improvethe stability of the visual readout. If, for instance, the readout isalternating between two pulses or counts, the visual display willflicker when counting by displayed increments of ones. If only everyother pulse or count is displayed (i.e., counting by increments oftwos), the chances of observing the alternation will be reduced.

According to this invention, program circuit 180 overcomes the foregoingproblems in a manner now to be described. The connections in circuit 180perform two desirable functions. First, it provides the capability ofdividing the pulse train produced by converter 132. Second, it providesthe capability of counting by series of different displayed increments.The following examples of the program circuit connections are given:

I. A readout of a l0,000-pound gross weight counting in displayedincrements ofones (FIG. 4).

2. A readout of a 10,000-pound gross weight counting in displayedincrements of twos (FIG. 5).

3. A readout of a 10,000-pound gross weight counting in displayedincrements of fives (FIG. 6).

4. A readout of a 5,000-pound gross weight counting in displayedincrements of ones (FIG. 6A).

5. A readout of a 50,000-pund gross weight counting in displayedincrements of fives (FIG. 7).

Advantageously, each of the program circuit connections for theforegoing conditions is provided on a separate printed circuit card.Accordingly, five circuit cards 180a (FIG. 4), 1801; (FIG. 5), 1800(FIG. 6), l80d(FIG. 6A), and l80e (FIG. 7) are shown for the fiveconditions mentioned above.

Referring to FIG. 4, the program connections provided on card 180a forreading out a l0,000-pound gross weight by counting in displayedincrements of ones, is as follows:

Line 150 is connected by a conductor 210 to the pulse input terminal orpin of the divide-by-two stage of counter 160; the data output pin A atthe divide-by-two stage of counter 160 is connected by a conductor 212to the corresponding weightof-one data input pin at latch 172; the dataoutput pin B at the divide-by-five stage of counter 160 is connected bya conductor 214 to the weightof-two data input pin of latch 172; thedata output pin C at the divide-by-five stage of counter 160 isconnected by a conductor 216 to the weight-of-four data input terminalof latch 172; and the data output terminal D at the divide-by-five stageof counter 160 is connected by a conductor 218 to the weight-of-eightdata input terminal of latch 172.

Circuit card 180a has two additional circuit connections indicated byconductors 219 and 220. Conductor 219 connects output pin A of counter160 to the data input pin of the divideby-five stage in counter 160,thus transferring the output of the divide-by-two stage to the input ofthe divide-by-five stage. Conductor 220 connects the data output pin Dof counter 160 to the data input pin of the divide-by-two stage incounter 161 to thus provide a transfer of data to counter 161.

With the circuit connections shown in FIG. 4, the binary data bits onoutput pins A, B, C, and D will be transferred in parallel to the latchdata input pins of corresponding weights. These connections togetherwith the direct connection from converter 132 to the input pin of thedivide-by-two stage of counter 160 and the transfer of data from pin Aof counter 160 to the input of the divide-by-five stage in counter 160will cause the units module of device 170 to advance the displayed countby one for each pulse supplied by converter 132. Thus, the parts orpulses will be totaled and displayed by counting in displayed incrementsof ones.

Referring now to FIG. 5, the circuit for displaying a gross weight of10,000 pounds counting in displayed increments of twos, is the same asthat shown in FIG. 4 except that conductor 212 has been removed. Inaddition, the weight-of-one data input terminal of latch 172 is tied toground as indicated at 221. Since the remaining circuit connections oncircuit card 180b are the same as those on card 180a, like referencenumerals have been applied to designate the conductors on card lb.

Alternatively, the weight-of-one data input pin of latch 172 may beconnected to a voltage source for supplying a logical l depending uponthe logic that is utilized.

With the circuit connections shown in FIG. 5, it will be appreciatedthat only counts corresponding to every other analog-to-digitalconverter pulse is supplied to and memorized by latch 172. Since thedata bit information on output pin A or counter 160 is not transferredto latch 172 and since the weight-of-one data input pin of latch 172 isgrounded, the state on the corresponding output pin of latch 172 willnot change states. Thus, for example, the display in the units module ofdevice 170 will be zero, two, four, six, and eight.

Referring to FIG. 6, the circuit connections that are made card circuitcard 1806 for displaying a gross weight of 10,000 pounds by counting indisplayed increments of fives are as follows:

Line is connected by a conductor 222 to the data input pin of thedivide-by-five stage in the pre-stage divider 194. The D-output pin atthe divide-by-five stage of divider 194 is connected by a conductor 224to the data input pin of the divide-by-two stage in counter 160. Thedata output pin A of the divide-by-two stage in counter is connected bya conductor 226 to the weight-of-one data input terminal of latch 172.The data output pin A of counter 160 is also connected through aconductor 228 to the weight-of-four input pin of latch 172. In addition,the data output pin A of counter 160 is connected through a conductor230 to the data input pin of the divide-by-two stage in counter 161.Both the weight-oftwo data input pin and the weight-of-eight data inputpin of latch 172 are connected to ground as indicated as 232. Bysupplying the weight-representing pulse stream of converter 132 to theinput of the divide-by-five stage of divider 194 and by applying theoutput of the divide-by-five stage of divider 194 to the data input pinof the divide-by-two stage in counter 160, only one count will betransferred to'the divide-by-two stage of counter 160 for every fivecounts or pulses applied to the input of the divide-by-five stage individer 194. Thus, the divide-by-five stage of divider 194 effectivelydivides the incoming count by five. If, for example, converter 132supplies a pulse train of 10,000 pulses to the divide-by-five stage ofdivider 194, only 2,000 counts will be transferred to the input of thedivide-by-two stage in counter 160.

However, the A output pin at the divide-by-two stage in counter 160 isnow connected by the circuit connections on card 1800 to both theweight-of-one data input pin and the weight-of-four data input pin oflatch 172. Thus for every fifth pulse supplied by converter 132, thelogical state at the weight-of-one input pin and the weight-of-fourinput pin of latch 172 will change. The BCD data word transferred to andlatched in at the data output pins of latch 172 will therefore be either0000 or 0101. As noted from the truth table in FIG. 3, the data words0000 and 0101 will be translated by device respectively into zero and 5,so that the units module of device 170 will alternately display a zeroand a five. If, for example, the display of the units module of deviceis at zero, no change will occur until the fifth of the first fivepulses are supplied by converter 132. On the fifth pulse, the logicalstates at the weight-of-one data input pin and the weight-of-four datainput pin of latch 172 will change concomitantly from a 0 to a l, and ifthis information is memorized, the number displayed in the units moduleof device 170 will change from zero to five. It therefore will beappreciated that a gross weight of 10,000 pounds will be counted out bycounting in displayed increments of fives. v

In FIG. 6 it will be noted that the divide-by-five stage of counter 160is effectively removed from the active circuit since no counts aresupplied to it and since its three data output pins B, C, and D aredisconnected from the remainder of the circuit. The count transfer fromcounter 160 to counter 161 is effected by conductor 230, thustransferring the count on the A-output pin of counter 160 to the datainput pin of the divide-by-two stage in counter 161.

Referring to FIG. 6A, the circuit connections that are made in circuitcard 180d for displaying a gross weight of 5,000 pounds by counting indisplayed increments of ones is as follows:

Line 150 is connected by a conductor 234 to the data input pin of thedivide-by-two stage in divider 194; the data output pin A at thedivide-by-two stage of divider 194 is connected by a conductor 236 tothe data input pin of the divide-by-two stage in counter 160; thedataoutput pin A of counter 160 is connected by a conductor 237 to theweight-of-one data input pin of latch 172; the data output pin B ofcounter 160 is connected by a conductor 238 to the weight-of-two datainput pin of latch 172; the data output pin C of counter 160 isconnected by a conductor 239 to the weight-of-four data input pin oflatch 172; the data output pin D of counter 160 is connected by aconductor 240 to the Weight-of-eight data input pin of latch 172; thedata output pin A of counter 160 is also connected through a conductor241 to the data input pin of the divide-by-five stage in counter 160;and the D-output pin of counter 160 is also connected through aconductor 242 to the data input pin of the divide-by-two stage incounter 161.

With the foregoing circuit connections on card 180d it will beappreciated that the divide-by-two stage in divider 194 is now operativeto divide the converter-produced pulse train by two. As a result, onlyone count will be transferred to the divide-by-two stage of counter 160every two pulses applied by converter 132 to the input of thevdivide-by-two stage of counter 160. Furthermore, it is clear that thedata output pins A, B, C, and D will be connected in parallel to thecorresponding data input pins of latch 172 similar to the connectionsshown in FIG. 4. Also the transfer of the count from the divide-by-twostage of counter 160 to the divide-by-five stage of counter 160 and thetransfer of the count from the D output pin of counter 160 to the datainput pin of the divide-by-two stage in counter-l61 is the same as thatshown in FIG. 4.

Accordingly, only every other converter-produced pulse is counted by theBCD counter circuit so that the logical states on the weight-of-one datainput pin of latch 172 will change only on the application of everyother converter-produced pulse. In other words, every other pulsesupplied by converter 132 will cause the logical states at the datainput pins of latch 172 to change as follows: 0000 to 0001 to 0010 to0011 to 0100 and so on. A gross weight of 5,000 pounds will therefore becounted by counting in displayed increments of ones.

Referring to FIG. 7, the circuit connections that are made in theprinted circuit card l80e for displaying a gross weight of 50,000 poundsby counting in displayed increments of fives are the same as that shownin FIG. 6 except that conductors 222 and 224 have been replaced by aconductor 244 for directly connecting line 150 to the data input pin ofthe divideby-two stage in counter 160. As 'a result, divider 194 isbypassed and-is out of the active circuit. The remaining connectionsfrom counter 160 to latch 172 and to counter 161 are the same as thatshown in FIG. 6. Accordingly, like reference numerals have been appliedto designate like conductors on card l80e. In addition, theweight-of-two data input pin and the weight-of-eight data input pin oflatch 172 are connected to ground as in card 1800. Counting willtherefore be in displayed increments of fives, for the memorized dataword on the output pins of latch 172 will either be 0000 or 0101. Thus,readout will be displayed in increments of fives, but as distinguishedfrom the circuit shown in FIG. 6, each pulse produced by converter 132will be counted, and each counted pulse will have a correspondingreadout value of five pounds since each count, upon being memorized,will cause the units module in device 170 to increase in five poundincrements. For the fivedecade counter shown, therefore, an input of10,000 pulses will produce a display of 50,000 pounds.

Advantageously, circuit cards 180a-180e are interchangeable with eachother so that a selected circuit card may be mounted in a suitableunshown socket assembly that provides the necessary inter-connections tothe other, previously mentioned printed circuit modules and otherportions of the overall circuit, as required. With the three10,000-pound circuit cards 180a, 180b, and 180c, the circuit 89 mayselectively and conveniently be converted to count in displayedincrements of ones, twos or fives. For example, if card 1800 is incircuit 89 and it is later desired to count by displayed increments oftwos instead of ones, it is only necessary to replace card 180a withcard 1801;. If it is desired to count and display 10,000 pounds bydisplayed increments of fives instead of ones or twos, then card 1800 isplaced on the socket assembly in place of either card 180a or 180b.

In addition to the convenience that is afforded by the foregoingarrangement, improved stability in the readout may be achieved bycounting in displayed increments of twos or fives instead of ones. Ifthe converter pulse train output is alternating between two pulses, forexample, the alternation will be observed in the form of a flickeringdisplay when circuit card 180a is being used. If card 180a is replacedwith either card lb or 1800, the chances of observing the alternationwill be reduced. As a result, a more stable reading is achieved.

Counting in displayed increments greater than ones, such as twos orfives, enables the same 10,000-pulse converter (i.e., converter 132) tobe utilized for reading out gross weights which numerically exceed themaximum number of pulses that the analog-to-digital converter is capableof producing. Consider, for example, the application of circuit 89 withthe 10,000-pulse converter. It readily matches a 10,000-pound grossweight scale, for each converter produced pulse will be the equivalentof 1 pound. In accordance with the present invention, the same circuit89 with the 10,000-pulse converter may optionally be applied to a50,000-pound gross weight scale simply by replacing card 180a with card1802. In addition, the same high gain of amplifier 102 will be utilized.

If it is desired to apply circuit 89 with its 10,000-pulse converter toa 5,000-pound gross weight scale, it is only necessary to place circuitcard 180d in the circuit in place of any card that may already be in thecircuit. If converting from a 10,000- pound gross weight to a5,000-pound gross weight, it will be noted that the same high span thatwas provided at amplifier 102 for the 10,000-pound gross weight isutilized for the 5,000-pound gross weight. In this embodiment,therefore, a gross weight of 5,000 pounds will produce ananalog voltagelevel of 10 volts, thereby avoiding the objectionable adjustmentdownward of the available gain as required in conventional systems.

With this invention, therefore, the amplifier gain is maintained at itsmaximum to maintain a high-signal-to-noise ratio. Furthennore, the fullcapacity of converter 132 will be util- .ized, namely 10,000 pulses for5 ,000 pounds so ,that each converter output pulse will be produced by arelatively high increment of the analog signal.

Furthermore, in converting, for example, from a 10,000- pound grossweight to a 5,000-pound gross weight, the counted parts (i.e., the partscounted in counters -164) will only be one-half of the pulses producedby converter 132. In comparison, conventional systems will count all ofthe weight-representing, converter-produced pulses. By reducing thenumber of counted parts or pulses the system of this invention willprovide greater accuracy and stability as compared with prior systems.Consider, for example, an error of one part in the pulse train producedby converter 132. In conventional systems this error will appear in thereadout. But by dividing at a pre-stage divider and thereby counting sayevery other part, the error of one part will not appear in the readout.

From the foregoing, it is evident that the accuracy and resolution ofthe system of this invention is higher than that of the previouslydescribed conventional systems.

In place of circuit cards l80a-180e it will be appreciated that thedesired connections in program 180 may be achieved by other means suchas jumpers or patchcords, switches, relays, field effect transistors, orelectronic switches.

In FIG. 1 circuit 89, comprising amplifier I02, filter 130, converter132, counter circuit 142, latch network 154, and the readout devices170-184, was described as applied to a batch weighing system. It will beappreciated, however, that circuit 89 of this invention has numerousother applications as in, for example, motion weighing systems ingeneral, and particularly in vehicle or article weighing systems. Avehicle weighing system is illustrated in FIG. 8, wherein a suitableplatform scale mechanism 300 supports a platform 302 for receiving atruck indicated at 304.

The scale mechanism 300 has an output lever 306 which is connected toload cell 86 in any appropriate, known manner. Load cell 86 is connectedto summing junction 100 as previously described. The remainder of theconditioning and digital readout circuit is the same as circuit 89except for the addition of a tare circuit which will be described lateron. Accordingly, like reference numerals have been applied to designatelike components in conditioning and readout circuit shown in FIG. 8,

Instead of connecting scale mechanism 300 to a single load cell asillustrated in FIG. 8, it will be appreciated that platform 302 may besupported directly on a plurality of load cells which also arepreferably of the strain gauge type. The summation of output voltagesfrom such a plurality of load cells would be applied through a suitablecircuit to summing junction 100.

In the system shown in FIG. 8, a storage hopper or bin 310 is providedfor storing material to be delivered to the vehicle on platform 302. Theopen bottom of bin 310 is selectively closed by a discharge gate 312.Gate 312 is opened and closed by a suitable fluid drive motor 314. Avalve 316 is actuated by a solenoid 318 controls the supply and exhaustof fluid for operating motor 314. Solenoid 318 may be controlled by ananalog cutoff circuit 320 which is essentially the same as part ofcircuit 90.

The system shown in FIG. 8 is operative to deliver a preselected amountof material from bin 310 to the vehicle 304 on platform 302. Briefly,the truck is placed on platform 302 and is weighed by circuit 89 in themanner previously described. A tare circuit generally indicated at 322is then activated to tare out the weight of the truck on platform 302 bysupplying an analog signal voltage to summing junction 100 which isequal and opposite in sign to the existing weightrepresenting load celloutput voltage at junction 100. The load cell signal applied to summingjunction 100 at this time represents the weight of the truck and anydead load of the scale mechanism applied to load cell 86.

The portion of the load cell output signal voltage representing any deadload that is applied by the scale mechanism to load cell 86 is tared outby the signal voltage developed by the dead weight potentiometer 116.The portion of the load cell output signal voltage representing theweight of the vehicle on platform 302 will now be tared out by the taresignal voltage developed by circuit 322. It therefore will beappreciated that the signal voltage applied by circuit 322 to summingjunction 100 will cause the algebraic summation of signals at junction100 to go substantially to zero. A balanced signal voltage conditionwill therefore exist at the input of amplifier 102.

Thus by applying the tare signal from circuit 322 to summing junction100, the level of the signal voltage at the output of amplifier 102 andconsequently at the output of filter 130 goes substantially to zero, andthis signal condition is applied to cut-off circuit 320 where it iselectrically compared by a suitable comparator 326 (see FIG. 9) with afixed, pre-set signal voltage representing the desired weight ofmaterial to be delivered to truck 304. The pre-set signal voltage isdeveloped by a potentiometer 328 (FIG. 9) in a weight selection circuitand is applied through a suitable summing resistor to a summing junction332 at the input of comparator 326. The output signal voltage of filteralso is applied to summing junction 332 through a suitable summingresistor. A IO-volt zener diode 334 is connected between summingjunction 332 and the output of comparator 326. Comparator 326 comprisesa suitable form of operational amplifier. The output of comparator 326is connected to one terminal of a relay 336, and the other terminal ofrelay 336 is connected to a suitable 10- volt source as shown. Thiscomparison and relay circuit is the same as that shown and described inthe previously identified U.S. application Ser. No. 658,229 (now U.S.Pat. No. 3,528,518). I

For the connections of zener diode 334 shown in FIG. 9, the polarity ofthe pre-set signal voltage developed by potentiometer 328 will benegative, while the polarity of the weightrepresenting signal voltage atthe output of filter 130 will be positive in this example. Thus when theoutput of filter 130 is less than the pre-set signal voltage developedby potentiometer 328, the algebraic summation of the signals will benegative to reverse bias diode 334. When diode 334 is reverse biased itwill hold the comparator output voltage at junction 338 at +10 volts. Asa result, there will be no voltage drop across the operating winding ofrelay 336, and relay 336 will therefore be de-energized.

Still referring to FIG. 9, the operating circuit for solenoid 318 hasbeen simplified and may basically comprise a selectively operated switch340 and a set of normally closed contacts 342 of relay 336. Switch 340,contacts 342, and solenoid 318 are connected in series across a suitablepower supply source indicated at 344.

From the foregoing it will be appreciated that when the magnitude of thepre-set signal voltage developed by potentiometer 328 exceeds the analogweight-representing signal voltage, a negative unbalanced signalcondition will exist at junction 332 to maintain relay 336 de-energized.As a result, contacts 342 will be closed. Thus, when it is desired todeliver material to the truck 304 on platform 302, the operator closesswitch 340 to energize solenoid 318 through contacts 342. Energizationof solenoid 318 operates valve 360 to supply pressurized fluid to motor314 in a manner to shift gate 312 to its opened position. Material inbin 310 will therefore descend by gravity into truck 304.

As material is delivered to the truck on platform 302, the output signalvoltage of load cell 86 will correspondingly increase. Since the signalvoltage representing the weight of the unloaded truck and any weightapplied by the scale mechanism to load cell 86 is tared out at junction100, the level of the signal voltage at the output of filter 130 will beclosely proportional to the amount of material delivered to the truck.This filter output signal voltage is continuously compared with thepre-set signal voltage from circuit 330 at comparator 326.

When the desired amount of material is delivered to truck 304 onplatform 302, the magnitude of the signal voltage supplied to summingjunction 332 from the output of filter 130 will. reduce the algebraicsummation of signals at junction 332 to zero. As a result, diode 334becomes forward biased to clamp the voltage at junction 338 tosubstantially zero volts. Consequently, a voltage drop is developed toenergize relay 336, and when relay 336 is energized contacts 342 areopened to de-energize solenoid 318. De-energization of solenoid 318results in the actuation of valve 316 for causing motor 314 to operatein a direction for closing gate 312. Delivery of material to the truckon platform 302 is therefore interrupted and the load of material intruck 304 will be the desired amount as determined by the pre-selectedsetting of potentiometer 328.

As shown in FIG. 8, the tare circuit 322 comprises a digitalto-analogconverter 350 for converting a BCD data word into its equivalent analogsignal voltage. As will be described in somewhat greater detail shortly,converter 350 is a sample and hold type circuit in that it will sample aBCD input and memorize it to maintain the equivalent analog signalvoltage at its output until the memory is erased. One suitable form ofconverter 350 as described above is the Analogic Corporation Model No.1216CDOA2AC.

Still referring to FIG. 8, the analog output of converter 350 isconnected by a line 352 to summing junction 100. Converter 350 has aseries of sets of BCD data word input pins corresponding to the latchesthat are utilized in latch network 154. Each set of BCD input pins hasfour pins for receiving a four-bit BCD data word. The BCD data outputpins of latches 172-176 are respectively connected to separate sets ofBCD data input pins at converter 350. It will be recalled that theinformation on the data output pins of latches 172-176'will be the datainformation which is memorized by latches 172-176 in response to thetransfer of a latching signal from converter 132.

In addition to the foregoing data input pins, converter 350 has a clear"pin 354 and a set" pin 356. A push button switch 358 has two terminalsrespectively connected to ground and to the clear" pin 354. Clear pin354 is also connected through a resistor 360 to the positive terminal ofasuitable power supply source such as 5 volts as shown. This positive5-,volt power source terminal is also connected through another resistor362 to one contact of a further push button switch 364. The othercontact of switch 364 is connected to the set pin 356, and pin 356 isalso connected through a dropping resistor 366 to ground.

As shown, the data output pin of latches 172-176 are connected inparallel to the BCDdata input pins of converter 350 by multipleconductors indicated at 370, 371, 372, 373, and 374. For displayinggross weights up to 9999 pounds (effectivcly 10,000 pounds) multipleconductor 374 may be eliminated so that converter 350 need only convertfour, fourbit data words into an analog signal. For displaying grossweights greater than 10,000 pounds (say 50,000 pounds) multipleconductor 370 may be eliminated with some slight loss of accuracy sothat converter 350 again will be required to convert only four four-bitdata words.

Switches 358 and 364 are normally open as shown, and when it is desiredto have converter 350 memorize the BCD data information at the outputpins of latches 172-176, switch 364 is momentarily'closed to apply thepositive going voltage from source 375 to the set" pin 356. At thisinstant, con- I verter 350 will memorize-the BCD-data informationsupplied to its data input terminals and will convert the BCDdatainformation into the equivalent analog signal voltagewhich isapplied over line 352 to summing junction 100. The sampled signalmemorized by converter 350 will be held even through the datainformation at the data output pins of latches 172-176 changes after thesampling.

From the foregoing circuitry it is clear that when the truck 304 isplaced on platform 302, circuit 89 functions to provide the weight ofthe vehicle in terms of BCD data information at the output data pins oflatches 172-176. When switch 364 is momentarily closed, this datainformation is sampled and memorized by converter 350, and converter 350will therefore feed back the equivalent analog signal voltage to summingjunction 100. The logic is selected so that the analog tare signalvoltage on line 352 will be opposite in sign as compared with the loadcell signal voltage applied to junction 100. As a result, the algebraicsummation of signal voltages at summing junction IOOwiIIreduce tosubstantially zero when switch 364 is momentarily closed after truck 304is placed on platform 302.

When it is desired to remove the tare signal voltage applied by line 352to summing junction 100, switch 358 is closed momentarily to momentarilyclamp the clear" pin 354 to ground. By clamping pin 354 to ground,-thedata information memorized by converter 350 is erased to prepareconverter 350 for another taring operation.

As shown in FIG. 8A, tare circuit 322 is replaced by a-tare circuit 390.It will be appreciated, particularly as this description proceeds, thatthe overall conditioning and readout circuit 89 may optionally beequipped with both tare circuits 322 and 390 or with either one of thetare circuits 322 and 390 depending upon the application of the weighingsystem. I

Circuit 390 comprises a potentiometer 392'having a resistor 394 and amovable wiper or am 396. Resistor 394 is connected across a suitablesource of power supply as-shown, and wiper 396'is adjusted alongresistor 394 to provide on wiper 396 the desired analog tare signalvoltage.

Wiper 396 is connected through a voltage follower 398 to one terminal ofa resistor 400. Wiper 396 is also connected through voltage follower 398to one contact of a pair 401 in a double pole tare-set switch 402. Theother contact of pair 401 is connected to the line or channel 406 whichapplied the output of filter 130 to the input of converter 132. Theother contact pair of switch 402 is indicated at 408 in line 406. Thecontacts of pair 408 are respectively connectedto the output of filter130 and the input of converter 132 as shown. Thus when switch 402 is inthe position shown, it completes a circuit connection between the outputof filter130 and the input of converter 132.. When switch 402 isactivated to its other position, it interrupts or breaks the circuitconnection between the-output of filter 130 and the input of converter132 and completes the circuit across the contacts of pair 401 forcompleting a circuit connection from the output of voltage follower 398to the input of converter 132. Thus in its illustrated position, switch402 applies the weight-representing filter output voltage to the inputof converter 132. In its non-illustrated position, switch 402 replacesthe weight-representing analog signal voltage at the input of converter132 with the output signal voltage of voltage follower 398, and theoutput voltage of follower 398 will be the analog tare signal voltage onwiper 396 of potentiometer 392.

With continued reference to FIG. 8A, the other terminal of resistor 400is grounded as shown, and resistor 400 forms a part of a potentiometer412 having a movable wiper or arm 414 which is adjustable along resistor400. Wiper 4l4 is connected through another voltage follower 416 to onecontact of a contact pair 422 in a gross-net double pole switch 420. Theother contact of pair 422 is connected to summing junction 100. Thesecond contact pair of switch 420 is indicated at 426', and the contactsof pair 426 are respectively connected to ground and to summing junction100. When switch 420 is in its illustrated position ground or zeropotential is applied to junction through the switch. When switch 420 isactuated to its second position at the contact pair 422, it completes acircuit connection for applying the signal voltage at wiper 414 tosumming junction 100. Circuit 390, as will now be described, may beutilized to apply a tare signal voltage to summing junction 100 insteadof utilizing circuit 322.

To employ circuit 390 for setting a desired tare signal into the system,it is first necessary to ascertain the weight of the article to be taredout. In the example shown in FIG. 8, it is therefore necessary todetermine the weight of truck 304.

Sometimes the tare weight of the truck is printed on the vehicle. If itis not, the unloaded truck is placed on platform 302 and its weight thenmay be read out at display device 170.

After the weight of the truck is ascertained, switch 402 is depressed tocomplete a circuit across the contacts of pair 401. By depressing switch402, the circuit connection between filter and converter 132 is isinterrupted and by completing the circuit across the contacts ofpair401,'the potentiometer wiper 396 will be connected through voltagefollower 398 to the input of converter 132. Thus, actuation of switch402 to its unillustrated position replaces the weight-representinganalog voltage signal with the signal developed by potentiometer 392.Converter 132, which is preferably of the bipolar type as hereinafterdescribed, will now convert the analog signal developedby potentiometer392-into a pulse train in the manner described. This pulse train isloaded into the counter circuit 142 and when converter 132 supplies thelatching ulse, the count in circuit 142 is memorized by the latchingcircuit 154. The memorized BCD data information at network 154 will bedisplayed in visual form by device 170 and/or printed form by printer182. Display device 170 will therefore read out the analog signalvoltage applied to wiper 396 in terms of weight during the time that theoperator is adjusting wiper arm 396. Thus the operator will be able toobserve the tare weight while he is making the adjustment of the tarewith wiper arm 396.

When the operator completes the tare adjustment at potentiometer 392, heactuates switch 402 to its illustrated position to thereby replace thesignal voltage developed by potentiometer 392 with theweight-representing filter output signal voltage. 1f cutoff circuit 320is to be utilized to dispense an accurate, pre-selected amount ofmaterial to truck 302, switch 420 is depressed to complete a circuitacross the contacts of pair 422 before the delivery of material isinitiated. As a result, the adjusted tare signal voltage on wiper arm396 will be applied through voltage followers 398 and 416 to summingjunction 100 with a polarity that is equal and opposite to the load celloutput signal voltage at junction 100. As a result, the algebraicsummation of the signal voltages at junction 100 will be reducedsubstantially to a zero level. Thus, the signal voltage at the output offilter 130 and, consequently, the signal voltages applied to converter132 and to circuit 320 will be reduced essentially to a zero level.Switch 340 (FIG. 9) is now actuated to open gate 312 for discharging thepre-selected desired amount'of material to truck 304 in the mannerpreviously described.

It will be appreciated that circuit 320 is an optional feature for usewhen it is desired to dispense an accurate, pre-selected amount ofmaterial into the vehicle or other container on platform 302. If, on theother hand, it is merely desired to fill truck 304 to its capacity andto thereafter determine the weight of material loaded into the truck,circuit 320 is not utilized.

Instead, the tare at potentiometer 392 is set by operation of switch 402in the previously described manner. Then, material is dispensed intotruck 304 on platform 302. During this time, switch 420 may be left inits illustrated, gross-weight position, or it may be actuated to itsunillustrated net weight position. If switch 420 is left in itsillustrated, gross-weight position, the tare signal voltage developed bypotentiometer 392 will not be applied to summing junction 100. As aresult, the load cell output signal voltage that is amplified andfiltered will be the gross weight or the sum of the weights of thevehicle and the amount of the material loaded into the the vehicle. As aresult, device 170 will display the gross weight or more specificallythe sum of the weights of truck 304 and the material delivered to truck304. This gross weight may be printed out by printer 182. I

When it is desired to determine the amount of material delivered totruck 304, switch 420 is depressed to complete a circuit across thecontacts of pair 422, thereby applying the tare signal voltage developedon wiper 396 to summing junction 100. This tare signal voltage willeffectively cancel out the portion of the load cell signal voltagerepresenting the weight of the truck so that the algebraic summation ofsignal voltages at summing junction 100 will be the net weight or, morespecifically, the weight of the material delivered to the truck.

Thus, the analog signal voltage representing the weight of materialdelivered to truck 304 will be applied to converter 132 and willconsequently be displayed in digital form by device 170. This net weightalso may be printed out by selective operation of printer 182.

The purpose of potentiometer 412 and voltage follower 416 is to cancelout the gain in the conditioning amplifier 102 so that the signalvoltage level at the output of amplifier 102 will have that value whichis furnished by potentiometer 392 and follower 398.

In comparison with tare adjustments such as, for example, calibratedthumb wheel circuits, circuit 390 of this invention provides a moreconvenient, less expensive arrangement for setting tare which utilizesthe available high resolution electrical equipment in circuit 89. Toachieve a correspondingly high resolution with conventional thumb wheelcircuits, it is normally necessary to add costly circuits to achieve thecomparable resolution which is available in circuit 89 and which isutilized by circuit 390 in this invention.

FIG. 10 shows a weigh-in and weigh-out arrangement utilizing circuits 89and 322. In this embodiment a storage hopper or bin 450 is suitablysuspended from and supported by one end of a fulcrumed lever 452 by aknife-edge assembly 454. Load cell 86 is connected to the other end oflever 452 as shown. Lever 452 is pivotally supported by a pivot andfulcrum assembly indicated at 456. A discharge gate 458 is provided forselectively closing the open-bottom of hopper 450 and is operatedbetween open and close positions by a suitable fluid motor 460. Circuits89 and 322 are the same as that shown in FIG. 8, like referencecharacters being applied to designate like components.

For the application shown in FIG. 10, converter 132 is required to be ofthe bi-polar type. A conventional bi-polar type of analog-to-digitalconverter will digitize analog signals of both polarities and usuallywill furnish signal conditions to indicate whether the input analogsignal is either positive or negative. Y

Hopper 450 may be in the form of a storage bin or silo. Circuits 89 and322 are utilized to determine the weight of material in hopper 450 aswell as the weight of material dispensed from hopper 450 as follows:

Hopper 450 is first filled to a suitable, desired level with switches358 and 364 in their illustrated, open positions. As a result, theanalog section of circuit 89 will apply to the input of converter 132 asignal voltage which is proportional to the weight of the material inhopper 450 after it is filled. This analog signal is digitized and readout in digit form. After hopper 450 is filled and before material isdispensed from hopper 450, switch 364 is momentarily closedto apply thenecessary signal condition to pin 356 that causes converter 350 tosample and memorize the BCD data information at the output of latchnetwork 154.

As a result, the data information memorized will be the weight ofmaterial in hopper 450 at the moment when switch 364 is closed beforematerial is dispensed. This BCD information is converted by converter350 into the equivalent analogsignal voltage and the equivalent analogsignal voltage isapplied by line 352 to summing junction as previouslydescribed.

Consequently, the algebraic summation at junction 100 will reduce tosubstantially a zero voltage level. The digital readout at device andprinter 182 will consequently be zero pounds. The apparatus is nowconditioned for dispensing material from hopper 450.

Assume, for example, that there are 10,000 pounds of material in hopper450 and that gate 458 is opened to dispense a portion of the load inhopper 450 into a truck or a container. Assume further that the amountdispensed was 2,000 pounds, thus leaving 8,000 pounds in hopper 450. Themagnitude of the load cell output signal voltage will now be less thanthe tare signal voltage supplied over line 352. As a result, thealgebraic summation of signal voltages at junction 100 will be anunbalanced negative signal condition. Thus a negative analog signalvoltage proportional to 2,000 pounds will be applied to the input ofconverter 132. Converter 132 will generate a pulse train in which thenumber of pulses will be equivalent to 2,000 pounds. Converter 132 willsupply a further signal indicating that the digitized signal voltage wasnegative. This signal may be applied over a channel 464 to a display466, which is conveniently located adjacent to the weight displayprovided by device 170. Accordingly, the combined readout of displaydevices 170 and 466 will indicate a negative 2,000 pounds, thusinforming the operator that 2,000 pounds of material was dispensed fromhopper 450.

If the operator now wishes to determine how much material is still inhopper 450, the operator momentarily closes switch 358 to apply groundpotential to the clear pin 354. As a result, the memorized datainformation in converter 350 will be erased and the tare signal voltageon line 352 will go to zero. Now, the algebraic summation of the signalvoltages at summing junction 100 will be proportional to the weight ofmaterial remaining in hopper 450. This weight is digitally displayed bydevice 170 and also may be printed out by printer 182.

As best shown in FIG. 2, a standard analog voltmeter 470 has a graduatedscale 472 expressed in terms of percentage of full scale voltage, whichin this example was taken as volts' Voltmeter 470 is provided with theusual coil 474 for moving a pointer along scale 472. Coil 474isconnected in series with resistor 476, as shown.

According to a further aspect of this invention, resistor 476 forms apart of a potentiometer 478 having a movable wiper or arm 480 which isadjustable along resistor 476 to selectively vary the voltage that canbe developed across coil 474. Wiper 480 is connected to a junction atthe output of filter 130 so that the voltage on wiper 480 will be thatof the weightrepresenting signal voltage at the output of filter 130.

By appropriately adjusting potentiometer 478, meter 470 will be made toread full scale (100 percent) when a full scale or gross weight signalvoltage (10 volts in the example of FIG. 2) is supplied at the output offilter 130. Potentiometer 478 thus effects a calibration so that thepercentage readings furnished by meter 470 will correspond to the ratioof the weight-representing signal voltage to, the full scale readingvoltage as determined by the gain provided the adjustmentof resistor104. 7 1

As an example, it may be desired to read out an'uncommon gross weight of9.000 pounds by l'pound graduations (i.e., counting in displayedincrements of ones). Circuit card 180a is placed in the circuit aspreviously described, and resistor 104 is adjusted to bring the maximumscale down to 9,000 pounds. Now, potentiometer 478 is adjusted to makethe maximum or 100 percent reading on meter 470 correspond to the filteroutput signal representing 9,000 pounds.

By adjusting potentiometer 478 to cause meter 470 to read full scale forany given gross weight, each of the meter scale graduations willrepresent the largest possible voltage. Accordingly, the accuracy of themeter readings will be improved. Meter 470, in addition to providing aninstantaneous reading of the weight-representing signal voltage, is alsouseful in troubleshooting for malfunctions, for it will indicate whetherthe problem is in the analog part of the circuit or in the digital partof-the circuit.

The invention may be embodied in other specific forms without departingfrom the'spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. In a weighing apparatus, a structure for receiving a load to beweighed, electrical signal producing means operatively associated withsaid structure for producing an electrical analog signal having a levelthat is a function of the weight of the load applied to said structure,an analog-to-digital converter, means for applying said analog signal tothe input of said converter, said converter being operative to produceat its output a train of electrical pulses in which the number of pulsesis representative of the level of the analog signal applied at the inputof said converter, electrical pulse counter means for producinginformation at its output that is'representative of the number of pulsecounts applied to its input, digital readout means, and circuitcompleting means for electrically connecting saidconverter to saidcounter'means to supply converterproduced pulses to the input of saidcounter and for electrically connecting the output of said counter meansto said readout means to transfer information supplied at the output ofsaid. counter means to said readout means for reading out thetransferred information in digital form, said circuit completing meansincluding preconditioned programmingv means for selectively providingany of the following: (1) division of the number of pulses in saidconverter-produced train of pulsesby at least one predetermined divisorand application of the counts representing the quotient to the input ofsaid counter means; and (2) the transfer of preselected information fromsaid counter means to said readout means for causing said readout meansto read out the count supplied to said counter means in equivalent oneof a plurality of different increments.

2. A method of providing a digital readout of the weight of a load, saidmethod comprising the steps of producing an electrical analog signalhaving magnitude that represents the weight of said load, convertingsaid analog signal into a weight-representing train of sequentiallyoccurring pulses wherein the number of pulses in said train is apredetermined multiple of the weight of said load, dividing the numberof pulses in said train by said multiple to provide a quotient of saidpulses in which the number is numerically equivalent to the weight ofsaid load, counting the number of pulses in said quotient, and providinga digital readout that is determined by the number of counted pulses.

3. In a weighing apparatus, a structure for receiving a load to beweighed, electrical signal producing means operatively associated withsaid structure for producing an electrical D.C. signal having a levelthat is a function of the weight of the load applied to said structure,an analog-to-digital converter, means for applying said D.C. signal tothe input of said converter, said converter being operative to produceat its output a serial train of electrical pulses having a fixedfrequency wherein the number of pulses in said train is representativeof a sample of said D.C. signal at the input of said converter,electrical pulse counter means comprising a plurality of cascaded decadecounters having outputs respectively representing separate digits of amulti-digit decimal number, Circuit completing means for electricallyconnecting the output of said converter to the lowest order decadecounter of said plurality of counters, means forming a part of saidcircuit completing means for dividing the number of pulses in said trainto provide a quotient in the form of a series of pulse counts, saidlowest order decade counter being connected to said dividing means forcounting in the counts in said quotient, and means connected to saidcounter means to provide a digital read-out of the counts that arecounted by said counter means. 4. A method of converting a signalconditioning and readout circuit from use with a first weighingapparatus having a first predetermined weighing capacity to use with asecond weighing apparatus having a second predetermined weighingcapacity wherein said first weighing capacity is at least twice as greatas said second weighing capacity, wherein each of said first and secondweighing apparatus has means for converting the weight of a load beingweighed into an electrical D.C. signal whose voltage level is a functionof the weight of said load, wherein said circuit has a signal amplifyingnetwork for amplifying saidD.C. signal, an analog-to-digit converter forconverting a sample of the amplification of said D.C. signal into apulse train of electrical pulses in which the number of pulses isrepresentative of the voltage level of said amplification of said D.C.signal and in which each pulse is representative of a predeterminedincrement of D.C. voltage, a pulse counter for counting the pulses insaid train, and a readout device connected to said counter for readingout the number of counted pulses in the form of a decimal number, andwherein said amplifying network is set to provide a predetermined gainfor amplifying the D.C. signal from said first weighing apparatus, saidmethod comprising the steps of increasing said predetermined gain to avalue substantially equal to said predetermined gain multiplied by apreselected integer than is greater than one, and dividing the number ofpulses in said train by said integer before said pulses are counted bysaid counter.

5. A method of digitally reading out a weight of a load being weighed ina weighing system having a signal producing means for providing a DC.signal whose voltage level is a function of the weight of said load, ananalog-to-digital converter connected to said signal producing means forconverting a sample of said DC. signal into a train of electrical pulsesin which the number of pulses is representative of the voltage level ofsaid DC. signal, a pulse counter connected to said converter forcounting the number of pulses in said train, and a readout deviceconnected to said counter for reading out the number of counted pulsesin decimal number form, said method comprising the steps of providingelectrical connections for transferring the data from said counter tosaid readout device, and selectively conditioning said electricalconnections to cause said read-out device to read out said decimalnumber in any of a plurality of different increments.

6. A method of digitally reading out a weight of a load comprising thesteps of producing a train of pulses in which the number of pulses isrepresentative of the weight of the load to be read out, counting atleast a predetermined number of the pulses in said train, andselectively conditioning a program circuit for reading out a decimalnumber representing the counted number of pulses in any of a pluralityof different, pre-selected increments.

7. The method defined in claim 6, wherein said pre-selected incrementsare increments of ones, twos, and fives.

8. The method defined in claim 6 comprising the step of dividing thenumber of pulses in said train by a pre-selected divisor before thepulses in said train are counted.

9. In a weighing apparatus, a structure for receiving a load to beweighed, signal producing means operatively associated with saidstructure for providing an electrical DC. signal whose voltage is afunction of the load applied to said structure, an analog-to-digitalconverter, an amplifier circuit electrically connected to said signalproducing means and said converter for amplifying said DC signal and forapplying the amplification of said DC. signal to the input of saidconverter, said converter being operative to produce at its output atrain of electrical pulses in which the number of pulses isrepresentative of the level of a sample of said amplification of saidDC. signal that is applied to the converters input, counter means,electrical circuit completing means connecting the output of saidconverter to the input of said counter means, means for selectivelyadjusting the gain of said amplifier circuit to provide for an increaseof a predetermined gain by a multiple thereof, means forming a part ofsaid circuit completing means for dividing the number of pulses in saidtrain by a divisor that is equal to said multiple to provide a quotientin the form of a series of pulse counts, said counter means beingconnected to said dividing means for counting the counts in saidquotient, and means connected to said counter means for providing adigital readout of the counted counts.

10. The weighing apparatus defined in claim 9, wherein said dividingmeans is operative to divide the number of pulses in said train by two.

11. The weighing apparatus defined in claim 9, wherein said dividingmeans is operative to divide the number of pulses in said train by five.

12. In a weighing apparatus, a structure for receiving a load to beweighed, electrical signal producing means operatively associated withsaid structure for producing an electrical analog signal having a levelthat is a function of the weight of the load applied to said structure,an analog-to-digital converter, means for applying said analog signal tothe input of said converter, said converter being operative to produceat its output a train of electrical pulses in which the number of pulsesis representative of the level of the analog signal applied at the inputof said converter, pulse counter means, circuit completing meansconnecting the output of said converter to the input of said countermeans, means forming a part of said circuit completing means fordividing the number of pulses in said train to provide a quotient in theform of a series of pulse counts, said" counter means being connected tosaid dividing means for counting the counts in said quotient, and meansconnected to said counter means for providing a digital readout of thecounted counts.

13. The weighing apparatus defined in claim 12, wherein the pulses insaid train are serially produced by said converter at a fixed frequencyand wherein said pulse counts are sen'ally applied to said countermeans.

14. The weighing apparatus defined in claim 13, wherein said dividingmeans has a divide-by-two stage, a divide-by-five stage, and terminalmeans to provide for the division of the number of pulses in said traineither by two or by five.

15. The weighing apparatus defined in claim 14, wherein said read-outmeans comprises a visual display device.

16. The weighing apparatus defined in claim 14, wherein said readoutmeans comprises a printer.

17. In a weighing apparatus, a structure for receiving a load to beweighed, electrical signal producing means operatively associated withsaid structure for producing an electrical analog signal having a levelthat is a function of the weight of the load applied to said structure,an analog-to-digital converter, means for applying said analog signal tothe input of said converter, said converter being operative torecurrently produce at its output a train of electrical pulses in whichthe number of pulses is representative of the level of the analog signalapplied at the input of said converter, and means operatively connectedto said converter for counting at least a portion of the pulses in saidtrain and for reading out in decimal number form the counted pulses inincrements greater than ones.

18. The weighing apparatus defined in claim 17, wherein said countingand readout means is operative to read out the counted pulses inincrements of twos.

19. The weighing apparatus defined in claim 17, wherein said countingand readout means is operative to .read out the counted pulses inincrements of fives.

20. The weighing apparatus defined in claim 17, wherein said countingand readout means comprises electrical counter means for counting atleast said portion of said pulses and for producing at its output abinary coded data word representative of the number of counted pulses,decoder and digital readout means for converting binary coded datainformation transferred to its input into a decimal number, and meansfor transferring only a portion of the binary coded data word suppliedat the output of said counter means to the input of sad decoder anddigital readout means.

21. The weighing apparatus defined in claim 20,'wherein said countermeans has a plurality of decade counters with one of said countersproviding a four-bit binary coded data word for a units decade in thereadout decimal number, and

. wherein said transfer means provides for the transfer of onlypreselected ones of the bits in said four-bit word to said decoder andreadout means.

22. In a weighing apparatus, a structure for receiving a load to beweighed, electrical signal producing means operatively associated withsaid structure for providing an electrical analog signal having a levelthat is a function of the weight of the load applied to said structure,an analog-to-digital converter electrically connected to said signalproducing means for converting a sample of said analog signal into atrain of electrical pulses in which the number of pulses isrepresentative of the level of said signal, pulse counter meanscomprising a series of cascaded decade counters having data outputsrespectively representing separate digits in a multi-digit decimalnumber, readout means for reading out said data outputs in the form of adecimal number, electrical circuit completing means for (a) connectingsaid converter to said counter means to apply converter-produced pulsesto be counted to the input of the lowest order decade counter of saidplurality of counters and (b) transferring said data outputs to saidreadout means, and preconditioned programming means and includingelectrical connections for transferring the data output of said lowestorder decade counter to said readout means to provide a readout of saiddecimal number of increments that are greater than one.

readout means, said first storage means having an input that isconnected by said programming means to the data output of said lowestorder decade counter, and said second storage means having inputsconnected directly to the data outputs of the remaining ones of saiddecade counters, said weighing apparatus further including means forcausing said first and second storage means to store the data suppliedto their inputs by said electrical circuit completing means.

i a na nn-

1. In a weighing apparatus, a structure for receiving a load to beweighed, electrical signal producing means operatively associated withsaid structure for producing an electrical analog signal having a levelthat is a function of the weight of the load applied to sAid structure,an analog-to-digital converter, means for applying said analog signal tothe input of said converter, said converter being operative to produceat its output a train of electrical pulses in which the number of pulsesis representative of the level of the analog signal applied at the inputof said converter, electrical pulse counter means for producinginformation at its output that is representative of the number of pulsecounts applied to its input, digital readout means, and circuitcompleting means for electrically connecting said converter to saidcounter means to supply converter-produced pulses to the input of saidcounter and for electrically connecting the output of said counter meansto said readout means to transfer information supplied at the output ofsaid counter means to said readout means for reading out the transferredinformation in digital form, said circuit completing means includingpreconditioned programming means for selectively providing any of thefollowing: (1) division of the number of pulses in saidconverter-produced train of pulses by at least one predetermined divisorand application of the counts representing the quotient to the input ofsaid counter means; and (2) the transfer of preselected information fromsaid counter means to said readout means for causing said readout meansto read out the count supplied to said counter means in equivalent oneof a plurality of different increments.
 2. A method of providing adigital readout of the weight of a load, said method comprising thesteps of producing an electrical analog signal having magnitude thatrepresents the weight of said load, converting said analog signal into aweight-representing train of sequentially occurring pulses wherein thenumber of pulses in said train is a predetermined multiple of the weightof said load, dividing the number of pulses in said train by saidmultiple to provide a quotient of said pulses in which the number isnumerically equivalent to the weight of said load, counting the numberof pulses in said quotient, and providing a digital readout that isdetermined by the number of counted pulses.
 3. In a weighing apparatus,a structure for receiving a load to be weighed, electrical signalproducing means operatively associated with said structure for producingan electrical D.C. signal having a level that is a function of theweight of the load applied to said structure, an analog-to-digitalconverter, means for applying said D.C. signal to the input of saidconverter, said converter being operative to produce at its output aserial train of electrical pulses having a fixed frequency wherein thenumber of pulses in said train is representative of a sample of saidD.C. signal at the input of said converter, electrical pulse countermeans comprising a plurality of cascaded decade counters having outputsrespectively representing separate digits of a multi-digit decimalnumber, circuit completing means for electrically connecting the outputof said converter to the lowest order decade counter of said pluralityof counters, means forming a part of said circuit completing means fordividing the number of pulses in said train to provide a quotient in theform of a series of pulse counts, said lowest order decade counter beingconnected to said dividing means for counting in the counts in saidquotient, and means connected to said counter means to provide a digitalread-out of the counts that are counted by said counter means.
 4. Amethod of converting a signal conditioning and readout circuit from usewith a first weighing apparatus having a first predetermined weighingcapacity to use with a second weighing apparatus having a secondpredetermined weighing capacity wherein said first weighing capacity isat least twice as great as said second weighing capacity, wherein eachof said first and second weighing apparatus has means for converting theweight of a load being weighed into an electrical D.C. signal whosevoltage level is A function of the weight of said load, wherein saidcircuit has a signal amplifying network for amplifying said D.C. signal,an analog-to-digit converter for converting a sample of theamplification of said D.C. signal into a pulse train of electricalpulses in which the number of pulses is representative of the voltagelevel of said amplification of said D.C. signal and in which each pulseis representative of a predetermined increment of D.C. voltage, a pulsecounter for counting the pulses in said train, and a readout deviceconnected to said counter for reading out the number of counted pulsesin the form of a decimal number, and wherein said amplifying network isset to provide a predetermined gain for amplifying the D.C. signal fromsaid first weighing apparatus, said method comprising the steps ofincreasing said predetermined gain to a value substantially equal tosaid predetermined gain multiplied by a preselected integer than isgreater than one, and dividing the number of pulses in said train bysaid integer before said pulses are counted by said counter.
 5. A methodof digitally reading out a weight of a load being weighed in a weighingsystem having a signal producing means for providing a D.C. signal whosevoltage level is a function of the weight of said load, ananalog-to-digital converter connected to said signal producing means forconverting a sample of said D.C. signal into a train of electricalpulses in which the number of pulses is representative of the voltagelevel of said D.C. signal, a pulse counter connected to said converterfor counting the number of pulses in said train, and a readout deviceconnected to said counter for reading out the number of counted pulsesin decimal number form, said method comprising the steps of providingelectrical connections for transferring the data from said counter tosaid readout device, and selectively conditioning said electricalconnections to cause said read-out device to read out said decimalnumber in any of a plurality of different increments.
 6. A method ofdigitally reading out a weight of a load comprising the steps ofproducing a train of pulses in which the number of pulses isrepresentative of the weight of the load to be read out, counting atleast a predetermined number of the pulses in said train, andselectively conditioning a program circuit for reading out a decimalnumber representing the counted number of pulses in any of a pluralityof different, pre-selected increments.
 7. The method defined in claim 6,wherein said pre-selected increments are increments of ones, twos, andfives.
 8. The method defined in claim 6 comprising the step of dividingthe number of pulses in said train by a pre-selected divisor before thepulses in said train are counted.
 9. In a weighing apparatus, astructure for receiving a load to be weighed, signal producing meansoperatively associated with said structure for providing an electricalD.C. signal whose voltage is a function of the load applied to saidstructure, an analog-to-digital converter, an amplifier circuitelectrically connected to said signal producing means and said converterfor amplifying said D.C. signal and for applying the amplification ofsaid D.C. signal to the input of said converter, said converter beingoperative to produce at its output a train of electrical pulses in whichthe number of pulses is representative of the level of a sample of saidamplification of said D.C. signal that is applied to the converter''sinput, counter means, electrical circuit completing means connecting theoutput of said converter to the input of said counter means, means forselectively adjusting the gain of said amplifier circuit to provide foran increase of a predetermined gain by a multiple thereof, means forminga part of said circuit completing means for dividing the number ofpulses in said train by a divisor that is equal to said multiple toprovide a quotient in the form of a series of pulse counts, said countermeans bEing connected to said dividing means for counting the counts insaid quotient, and means connected to said counter means for providing adigital readout of the counted counts.
 10. The weighing apparatusdefined in claim 9, wherein said dividing means is operative to dividethe number of pulses in said train by two.
 11. The weighing apparatusdefined in claim 9, wherein said dividing means is operative to dividethe number of pulses in said train by five.
 12. In a weighing apparatus,a structure for receiving a load to be weighed, electrical signalproducing means operatively associated with said structure for producingan electrical analog signal having a level that is a function of theweight of the load applied to said structure, an analog-to-digitalconverter, means for applying said analog signal to the input of saidconverter, said converter being operative to produce at its output atrain of electrical pulses in which the number of pulses isrepresentative of the level of the analog signal applied at the input ofsaid converter, pulse counter means, circuit completing means connectingthe output of said converter to the input of said counter means, meansforming a part of said circuit completing means for dividing the numberof pulses in said train to provide a quotient in the form of a series ofpulse counts, said counter means being connected to said dividing meansfor counting the counts in said quotient, and means connected to saidcounter means for providing a digital read-out of the counted counts.13. The weighing apparatus defined in claim 12, wherein the pulses insaid train are serially produced by said converter at a fixed frequencyand wherein said pulse counts are serially applied to said countermeans.
 14. The weighing apparatus defined in claim 13, wherein saiddividing means has a divide-by-two stage, a divide-by-five stage, andterminal means to provide for the division of the number of pulses insaid train either by two or by five.
 15. The weighing apparatus definedin claim 14, wherein said read-out means comprises a visual displaydevice.
 16. The weighing apparatus defined in claim 14, wherein saidreadout means comprises a printer.
 17. In a weighing apparatus, astructure for receiving a load to be weighed, electrical signalproducing means operatively associated with said structure for producingan electrical analog signal having a level that is a function of theweight of the load applied to said structure, an analog-to-digitalconverter, means for applying said analog signal to the input of saidconverter, said converter being operative to recurrently produce at itsoutput a train of electrical pulses in which the number of pulses isrepresentative of the level of the analog signal applied at the input ofsaid converter, and means operatively connected to said converter forcounting at least a portion of the pulses in said train and for readingout in decimal number form the counted pulses in increments greater thanones.
 18. The weighing apparatus defined in claim 17, wherein saidcounting and readout means is operative to read out the counted pulsesin increments of twos.
 19. The weighing apparatus defined in claim 17,wherein said counting and readout means is operative to read out thecounted pulses in increments of fives.
 20. The weighing apparatusdefined in claim 17, wherein said counting and readout means compriseselectrical counter means for counting at least said portion of saidpulses and for producing at its output a binary coded data wordrepresentative of the number of counted pulses, decoder and digitalreadout means for converting binary coded data information transferredto its input into a decimal number, and means for transferring only aportion of the binary coded data word supplied at the output of saidcounter means to the input of sad decoder and digital readout means. 21.The weighing apparatus defined in claim 20, wherein said counter meanshas a plurality of decade couNters with one of said counters providing afour-bit binary coded data word for a units decade in the readoutdecimal number, and wherein said transfer means provides for thetransfer of only preselected ones of the bits in said four-bit word tosaid decoder and readout means.
 22. In a weighing apparatus, a structurefor receiving a load to be weighed, electrical signal producing meansoperatively associated with said structure for providing an electricalanalog signal having a level that is a function of the weight of theload applied to said structure, an analog-to-digital converterelectrically connected to said signal producing means for converting asample of said analog signal into a train of electrical pulses in whichthe number of pulses is representative of the level of said signal,pulse counter means comprising a series of cascaded decade countershaving data outputs respectively representing separate digits in amulti-digit decimal number, readout means for reading out said dataoutputs in the form of a decimal number, electrical circuit completingmeans for (a) connecting said converter to said counter means to applyconverter-produced pulses to be counted to the input of the lowest orderdecade counter of said plurality of counters and (b) transferring saiddata outputs to said readout means, and preconditioned programming meansand including electrical connections for transferring the data output ofsaid lowest order decade counter to said readout means to provide areadout of said decimal number of increments that are greater than one.23. The weighing apparatus defined in claim 22 wherein said decimalnumber is read out in increments of twos.
 24. The weighing apparatusdefined in claim 22 wherein said decimal number is read out inincrements of fives.
 25. The weighing apparatus defined in claim 22wherein said converter serially produces said pulses at a fixedfrequency.
 26. The weighing apparatus defined in claim 25 wherein saidelectrical circuit completing means includes first and second signalstorage means having outputs connected to said readout means, said firststorage means having an input that is connected by said programmingmeans to the data output of said lowest order decade counter, and saidsecond storage means having inputs connected directly to the dataoutputs of the remaining ones of said decade counters, said weighingapparatus further including means for causing said first and secondstorage means to store the data supplied to their inputs by saidelectrical circuit completing means.